We propose to complete our measurement and comparison of the circular dichroism spectra of the following 12 synthetic double-stranded RNA polymers: poly(r(A).r(U)), poly (r(G).r(C)), poly (r(A-U).r(A-U)), poly(r(A-C).r(G-U)), poly(r(A-G).r(C-U)), poly (r(A-G-C).r(G-C-U)), poly(r(A-U-C).r(G-A-U)), poly(r(A-C-U).r(A-G-U)), poly(r(A-A-U).r(A-U-U)), poly(r(A-A-C).r(G-U-U)), and poly(r(A-C-C).r(G-G-U)). The CD spectra of these synthetic RNA sequences will then be used as a basis for analyzing the CD spectra of natural double-stranded RNAs from the virus particles of the fungus Penicillium chrysogenum and from phi6 Pseudomonas bacteriophage. From such analyses we should be able to determine the distributions of first-neighbor frequencies in these natural RNAs. We also plan to study the solution structure of a DNA-protein complex by small-angle neutron scattering. The complex we are studying consists of the gene 5 protein of fd phage and single-stranded DNA. This complex has an elongated helical structure and is an important intermediate formed during the production of the E. coli filamentous fd phage. We wish to determine whether the axial radius of the DNA is lesser or greater than the protein in the complex. We will do this by comparing the neutron scattering patterns obtained from complexes reconstituted with normal DNA and with deuterated DNA.